Does anyone think there is any real difference between cut and button rifling? I have always thought cut put less stress on the steal. But is it in my head that it really makes any difference?
I would get get about 1k out of my 6CM barrels. That was on 8 tubes. My accuracy expectations are pretty high. When you spend the effort and money to shoot matches well barrel are like race car tires if they are not in good shape you will not win the race.CP Donnelly was a student of PO Ackley and knew a great deal about rifle barrels and how to make them. He rifled them with a button. those that I have are very accurate and have maintained accuracy through several hundred rounds, including a 257 Wby, known as a barrel burner.
Very interesting! Thank you Ray!Cut involves a sharp edge being drawn through the barrel and removing the groove metal. Button involves a piece of metal with high spots for the grooves and low spots for the lands being drawn through the barrel and pushing metal to compress it. Hammer forged has a large piece of metal the shape of the desired interior of the barrel. It is placed in a barrel that is drilled out to groove size, then hammers pound the metal down into the shape of the insert.
Very interesting and thanks for providing this detailed explanation. I’ve heard the different rifling terms before, but wasn’t completely sure about the different processes.1. Cut Rifling
Cut rifling is the oldest method of rifling a gun barrel. The cut-rifling method removes metal from the surface of the bore to create the grooves using a single-bladed, hook-type cutter of groove width that is pulled through the cold barrel. It is sometimes called "hook rifling" after the fishhook-shaped cutter used. Cutter depth is adjustable, so that it removes only a small amount of metalona pass. Each groove must be cut individually with multiple passes of the cutter. The cutter is indexed to each groove in turn and positively rotated by the rifling machine using a sine bar.
Advantages of cut rifling:
The shape and number of grooves and groove depth can be easily changed as necessary.
Rifling twist rate may be easily changed as required.
Rifling twist is consistent from one end to the other.
Little or no additional stress is imposed on the barrel.
Cut-rifled barrels may be contoured after rifling.
Close tolerance can be held.
Disadvantages of cut rifling:
The process is slow and not well adapted to mass production.
Cut barrels normally cost more due to the slower manufacturing process.
Some metal alloys can not be cut.
A mistake or machine malfunction at the end of the process can prove wasteful.
Cut-rifled barrels must be lapped.
Many target shooters prefer cut-rifled barrels for their uniformity and close tolerance. The cut-rifling method is normally used on prototype or test barrels where only a small number will be made for experimental purposes.
2. Button Rifling
Button rifling is a modern method that creates the grooves in the cold surface of a rifle bore by displacing metal using a bullet-shaped, super-hard button of tungsten carbide. The rifling button has the reverse pattern of the groove profile ground into its surface. As the rifling button is pushed or pulled through the barrel, the groove pattern is ironed into the bore surface by displacement. There are several variations in button-rifling procedure. Some barrelmakers prefer to pull the button through the bore, while others prefer to push it through. In most cases, the button remains free to rotate during this process, dependent on the angle of the grooves in its surface to cause the desired degree of rifling twist. As variations in rifling twist may occur during this procedure, some barrelmakers affix the rifling button to a rod and positively rotate it with a sine bar.
Advantages of button rifling:
The procedure is fast and very economical, as only a single pass of the button is required to rifle a barrel.
Button rifling is well suited to mass-production methods with high output.
Button rifling leaves a smooth, bright finish inside the barrel that need not be lapped.
Button-rifled barrels are very accurate.
Bore and groove dimensions are very consistent.
Disadvantages of button rifling:
Button rifling creates stress in a barrel; high-quality button-rifled barrels must be stress-relieved after rifling.
Buttons are expensive and difficult to make.
Different groove configurations and different rifling twists require a new button.
The button-rifling system is not flexible.
Button-rifled barrels can be extremely accurate; more bench-rest records are held by shooters using guns with button-rifled barrels than by any other type. Button-rifled barrels are very common on modern centerfire and rimfire guns.
3. Hammer forging is an ultra-modern method of rifling a gun barrel that is well suited to high-volume production by large manufacturers such as government arsenals and commercial corporations that can afford the sophisticated machinery. This method begins with a metal barrel blank about 12 inches long and 2 inches in diameter with a hole in its center honed to a fine finish. A tungsten carbide mandrel with the pattern of the rifling lands and grooves machined into its surface in reverse relief is then inserted into the hole of the blank. A forging machine with a series of radially opposed hammers is then used to compress the blank inward against the mandrel. As the hammers compress the outer surface, the blank is reduced in diameter and lengthened, simultaneously creating the bore and rifling. If needed, hammer forging can form the chamber and throat as well as a fully profiled outer surface. The spiral tracks of the hammers can often be seen on the outer surface of hammer-forged barrels. Some manufacturers turn the barrels to remove this surface, while others leave it in place.
Barrel blanks may be hammer forged cold or hot. Hot hammer forging reduces the amount of effort that the hammers must exert on the blank, and can result in better grain structure and improved strength. However, hot hammer forging is more expensive and requires more sophisticated machinery. The cold hammer-forging process produces barrels of excellent quality. Hammer-forged barrels are very common on high-volume centerfire hunting rifles and pistols where their consistency and strength outweigh their accuracy capabilities. They are not common on match-grade or varmint barrels, as their accuracy is perceived to be inferior to cut- or button-rifling methods.
Advantages of Hammer Forging:
- Hammer forging consistently produces high-quality barrels.
- It can form chamber, throat and outer profile if necessary.
- It does not remove metal; there's no waste or chips.
- It produces barrels with excellent grain structure and high strength.
- Hammer forging produces superb bore finish, no lapping needed.
Disadvantages of Hammer Forging:
Copied from the NRA site.
- Machinery and mandrels are expensive.
- It's inflexible; changes in rifling require a new mandrel.
- Quality is very good, but not match grade.
- Hammer tracks are left on outer surface.
- Process introduces stress in the barrel; must be stress-relieved.
Thanks Mark!@CoElkHunter its a long story.
Cut rifling (or single point cut rifling) is the oldest method. Basically you pass a cutter inside the barrel, making a thread, noumerus passes for only one rifling to be made. Then the craftsman goes for next. It takes hours.
Speedy process is broaching, where 3-4-6 cutters are on one tool, and with one pass you start creating multiple rifling. Broaching is not frequent method, and I think if used today will be used for short barrels like for pistols.
Button rifling. Method without skill. Machine.
in Europe patented by Lothar Walther 1929, in USA patented by Remington in 40 ties.
in short, there is a negative of rifling, made of thungsten - called button.
Button is a bit wider then inner diameter of raw barrel. By force it is pushed through the raw barrel, and in process leaves barrel a bit "wider" with "engraved" rifling.
Button can be pushed (pushed button rifling) or pulled (pulled button rifling)
Hammer forging is Austrian steyr invention in 1939. This was developed for mass production of barrels for GMPG automatic weapons,. as they need barrel changes and barrel replacement frequently, especially on eastern front.
This technology was discovered by allies after end of ww2, on liberation of Europe.
Europan manufacturers loved it.
The raw barrel, very short and very thick is passed through the 4 - sides hammer press. Inside the barrel there is a negative of rifling,(not sure of english term) and 4 hammers are pressing from sides, and shape the barrel over the negative, the barrel moves through the press out and gets longer in lenght, thiner in thicknes and gets out with pressed in rifling.
For button rifling and hammer forging typical is the stress imposed to barrel material structure.
So next phase will be stress relieving.
It is done either by cryogenization of barrel, or thermal heating of barrel to extreme high of low temperatures and then by easy retrieving to room temp.
After that lapping and reaming follows. (lapping can be done by machine or by hand)
For hammer forging and button rifling skilled labor is not necessary, for cut rifling yes, skilled labor is necessary.
Final method, at least in theory, is chemical rifling process, and i have no idea how it is done. And is not common method.
I recall reading that Remington used Broaching gangs to rifle some of their rifles in the early 60sBroaching is not frequent method, and I think if used today will be used for short barrels like for pistols.
Button rifling. Method without skill. Machine.
All things being equal, including barrel maker skill, the differences are generally not measurable by us mere mortals.Does anyone think there is any real difference between cut and button rifling? I have always thought cut put less stress on the steal. But is it in my head that it really makes any difference?
Hammer forged has a large piece of metal the shape of the desired interior of the barrel. It is placed in a barrel that is drilled out to groove size, then hammers pound the metal down into the shape of the insert.